Bacillus thuringiensis is a gram-positive, soil-dwelling bacterium, the most commonly used biological pesticide worldwide. B. thuringiensis also occurs naturally in the gut of caterpillars of various types of moths and butterflies, as well on leaf surfaces, aquatic environments, animal feces, insect-rich environments, and flour mills and grain-storage facilities. It has also been observed to parasitize moths such as Cadra calidella—in laboratory experiments working with C. calidella, many of the moths were diseased due to this parasite.
Bacillus thuringiensis
Gram stain of Bacillus thuringiensis under 1000 × magnification
Agriculture enthusiasts examining insect-resistant transgenic Bt corn
An ovitrap collects eggs from mosquitoes. The brown granules in the water are a B. t. israelensis preparation that kills hatched larvae.
Caterpillars are the larval stage of members of the order Lepidoptera.
Euthalia aconthea (baron butterfly) caterpillar found in India
Caterpillar of Papilio machaon
A monarch butterfly (Danaus plexippus) caterpillar feeding on an unopened seed pod of swamp milkweed
Caterpillar cocoon on a pine tree branch.